By deep-drawing there is generally understood a compression-tension reshaping or compression reshaping of flatly shaped workpieces to form a hollow body open at one side or also only the shaping of bulges in the surface of the flatly shaped workpiece, in that a die presses the workpiece into a corresponding die plate.
Deep-drawing in the last-mentioned form finds use in, for example, the production of steps or tread elements and riser elements of escalators or of plates of moving walkways. A tread element forms the tread surface or stand surface for a user of the escalator or of the moving walkway and a riser element forms the visible front face of the step in the inclined part of the escalator. Through the deep-drawing there is achieved, with the stated elements, the shaping of a web/groove profile which notwithstanding its low weight is stiffer and narrower than can be achieved by a stamping method or a pressure moulding method or a rolling method. Moreover, the web profile or groove profile is provided with a plurality—of about 88 to approximately 112—of webs and grooves in an escalator step or moving walkway plate so as to guarantee better standing of the user and to allow liquids, particularly water, to drain away.
The preferred narrow web/groove profile is achieved in that a deep-drawing plate with projections, for example in the form of teeth, tines or prongs, is guided and moved relative to and/or comparatively and/or co-operatively and/or compatibly with respect to a tool with recesses, for example in the form of grooves. Comparatively means that not only the tool can be pressed against a stationary deep-drawing plate, but also that a movable deep-drawing plate can be pressed against a stationary tool. In addition, the tool can have the projections and the deep-drawing plate the recesses and thus be equipped in opposite manner. It is merely fundamental that projections are pressed into corresponding, complementary recesses.
However, a general disadvantage of deep-drawing is that the necessary ‘material deformation flow limit’ can contradict economic, industrial mass production. In the case of simultaneous deep-drawing of several grooves, which are preferably in a row closely adjacent to one another, the tear strength or yield point or breaking strength limit of the material is quickly exceeded. Consequently, for example, a pressure device is disclosed in the specification JP-A-62270224 in which the steel sheet is pressed onto an individual web tool or stamping tool and each web thus individually formed in succession.
Proceeding from the state of the art and the general problem of ‘material deformation flow limit’ in deep-drawing the object is set of finding a deep-drawing device or method steps which enables or enable simultaneous production of several, preferably all, desired webs and is thus more economic and faster than previously usual and customary.